Electric discharge display device



May 12,4 1931. s. RUBEN ELECTRIC DISCHARGE :DISPLAY 'DEVICE Filed Jung26,v 192e Suva/hbo@ SAMUEL RUBEN Al The operation of the former'Patented May-12,519.31

UNITED STATI-:s PATENT oFFicE BHUEL RUBEN, 0l' NEW YORK, N. YV.,ASSIGNOB TO RUBEN NEW YORK, N. Y., A CORPORATION Ol' remmers conrANY,oir nmwm m1302310 yDISCHARGE DISPLAY DEVICE application mea nine as,

This invention relates to improvements in 1- electric discharge displaydevices and the l! play devices employing electrical discharges throu lithe gaseous content of ltransparent containers and .to the means forpreparing them. The object of the invention is to provide at low costdurable display devices which i0 vemploy an electrical discharge throughmonatomic gases within a transparent container.

In the prior art there are two types of luminous display devicescommonly used as signs, employing electricaldischarge through conlinedgases in translucent veels; namely, the electrode type and the condenseror inductive discharge type, both having limitations which the devicesof my invention are designed to overcome.

stricted .through the absorption o the gas content b the electrode andconsequent reduction o pressure, b the sputterin of the electrode and bythe h potential dropof potential at the electrodes, with a resultantrelativelylpoor distribution of ener into the s and (fh temperatures ofthe e ectrodes.

e secon or inductive discharge type operstes only by currents of hi herfrequencies by electrostatic capacit disc arge and leaka currentsthrough t e glass or Vother die ectric walls of the container. In thistlype the electrode usually employed is a vsi ver coating on the outersurface of the glass container wall, forming a tubular electrode. As thedischar tric ,walls t vecurrent discharge through the gas is necessarilylimited and the glass walls soon become heated by dielectric hysteresislosses and ionic bumbardment, resulting in the puncturin'g of the wallor the localization of current to an area of high temperature. As glasshas a high negative resistance tempeinture coecient the inductiveproperties of the electric discharge is lost and aconductive onesupersedes it, resulting in the amplication of the limitations cited.

A device constructed accordin' to the terms et my invention consistsbroad y of a gransparent dielectric container, preferably must passthrough the dielecntuv 1826. Serial No. 118,885.

bular form, having therewithin in an atmosphere of monatomic gasalkaline electrodes, preferably supported without direct contact withthe container walls, with means for restricting or confining theirdischarge areas, also condenser .electrodes contactin with the otherelectrodes through a coatingo conducting resistance material on thesurface of the container wall.

The inner or conductiye discharge electrodes are of the alkalineI orsecond periodic group, magnesium being preferred because of itselectropositive character and its low cath-- ode drop of potential,making the temperature vrise or the ener loss at the surfacev negligibleas compare with that of the'elec- Atrodes used in the devices of theprior art.v Sputtering of these lelectrodes is avoided by the use ofinductive discharge or capacity electrodes maintained at a higherpotential than that of the'matgnesium electrodes. These magnesiumelectro have a further important that of. gas purification by absorbingall .save the menatomic gases, or the neon, helium, crypton and argongroup, and therefore, any

es, preferably in rod form, v ction; namely,

gas im uritylsuch as nitrogen and oxygen some o whic may be due to thedischarge of surface or occluded ases caused by thermal or electricalbombar ment, is absorbed and lbecomes inoccuous.

The device walls may be of quartz or of lead, lime or borate glass,depending upon the mechanical requirements. And the de- `vice may beloperated by high or lopr frequency alternatin current or by continuousor intermittent direct current. The conductive discharge electrodes arenot directly connected 'to the transformer, but throu a coating of aconductive resistance material on the exterior wall of the container.The electrode or gas reserve chamber is' referably convoluted because ofthepermitted increased gas reserve maintainable therein to the tube wallcaused purity and constancy electrodes.' This means a reduction of theoperating potential by producing a transverse field, iving a widercurrent distribution over t e electrode discharge surfaces and areduction of the space charge'around the electrodes; and, due to theresultant low current density the electrode sputtering is of. small manitu e. verse fiel is to cause a slight discharge to the externalelectrode, there y causing a liberation of physically adsor ed gases,due to the sputtering of the electrode material b the ionic bombardmentupon the elect e.

A quartz tube surrounding the ma esium rod or inner electrode restrictsthe discharge to a definite localized area, and as this material, evenwhen hot will not ionize,a sodium or silicate ionic discharge fromadjacent glass, is (prevented. Such discharges are a familiar efec't ingas discharge devices when the glass surface is too close to theelectrode.

The method of evalibating and filling the containers is im ortant asitis only by proper evacuation an gas discharging that the of pressure ofthe gas content caribe maintained. To effect the discharge'of alloccluded gases and vapors, while t e pressure is being reduced as faras. possible, the device should be raisedto the highest practicabletemperature and a. potential applied to the inner electrodes at the sametime, thisfassisting in electrostatically or by ionicbombardment,eiecting the discharge of occluded gases, all of which must be socompletely exhausted that practically no positive ionization can occurunder the iniiuence of the finally applied potential.

Sometimes it is desirable to discharge vsodium or potassium vaporthrough the container when hot, this practice being found in the priorart to materially assist in the reduction of water vapor from the innersurface of the container walls. When the device is thorouhlyevacuated,so that all occluded gases an vapors are exhausted, the desired gas isadmitted slowly into the container, the pumping system being then shutoii. To insure the final proper gas pressure a milliammeter is placed inseries with a transformer connected to the device and the gas to beemployed is admitted into the device until 'the maximum conductivity isindicated. The gas pressure is then further increased until theconductivity or luminosity decreases by about This excess allows for theabsorption of gas impurities, such as nitrogen and oxygen, and of someof the -admitted gas by the container wails and contained metal parts inthe process of cooling and ageing, maintaining the proper pressure. Aglass sign so prepa-red and having a tube length of about inches and .aninside diameter of about inch shows an imprac- One eiect of thetransquartz collars 8, to y quartz collars at the same time serving toticable luminosity when 5 milliamperes at 3000 the gas.

Reference is made to the accompan ing drawing of a preferred embodimento 'the invention. l

In the drawing,`1 represents a glass container having the display orluminous portion (Look) and its electrode or gas chamber 2, filled withneon gas in a volume as indicated electrically, about 20% beyond thepoint of maximum conductivity. At 3 are the magnesium conductivedischarge rod electrodes, having quartz collars' 8, about volts isapplied to them and connected by metal bandsl 6, and

conductor wires 7, with graphite coating 5, contacting vwith which areinductive discharge electrodes 4, connecting directly with,

transformer 9 and with generator 10.

By means of electrodes 4 and 6, the dischar d current ionizes thecontained as whic becomes. highly luminous, the ischarge from electrodes3, being confined by the.- exposed ends, the

prevent any sodium or. silicate ionic discharge from adjoining glasswalls. The inductive discharge from electrodes 4, not only assists inthe gas ionization but minimizes the eiiect of any possible sputteringof the magnesium electrodes 3. .The resistance drop through graphitecoating 5, gives the copper band terminal at 6 a lower potential for thedischarge from electrode 3.

1. An electric discharge device comprising, in combination, a containerhaving translucent dielectric walls "and, containin a monatomic gas andgas absorptive, con uctive discharge electrodes, with inductive dischare electrodes and means for maintaining said inductive dischar potentialthan said ot er electrodes. y

2. An electric discharge device comprising, a container havingtranslucent dielectric walls and containing a monatomic gas and gasabsorptive conductive dischar e electrodes, in combination withinductive discharge electrodes connected with said other electrodes by aconductive resistance material. i

3. Anelectric discharge device comprising, a container containing amonatomic gasand therewithin conductive composed of a material of Athesecond periodic grou in combination with inductive discharge e ectrodesand means for maintainin said inductive discharge electrodes at a hig erpotential than that of said other electrodes, said inductive dischargeelectrodes consisting ci conducting resistance material coating on anouter wall ci the container adjacentthe conductive electrodes.

a. An eiectric discharge device comprising, a container containing amonatomic gas a current of about iis discharge electrodes A andtherewithin conductive discharge electrodes composed of ma eslum, 1ncombmation with inductive disc arge electrodes and means for maintainin-charge electrodes at a igher potential than l -that of saidotherelectrodes b. connecting said inductive dis- 'the conductive dischargeelectro es with their adjacent inductive discharge electrodes by a ingresistance material on ,the outer wall of the container adjacent theother electrode.

7. An electric discharge device comprls'ing a container havingtherewithin a monatomic gas and conductive discharge electrodes composedo an electropositive gas absorptive material', shielded by a sleevecomposed of uartz, in combination with inductivedisc arge electrodesconsisting of coatings of a Vconducting resistance material on the outerwall of the container adjacent the other electrodes.

8. In -an electric discharge device, means for continuously occludingordinary gases and continuously liberating occluded or mechanicallyentangled. rare gases.

In t'estlmony whereof, SAMUEL RUBEN has signed his name to thisVspecification this 24th day of June, 1926.l

t SAMUEL RUBEN.

